The present invention is directed to a method for taking samples of and for analyzing fluid hydrocarbons, whereby the specimen is collected by sorption, is conveyed to an analysis means and is analyzed. The invention is also directed to a means suitable for the implementation of this method.
It is known that particularly volatile hydrocarbons frequently are the cause of serious environmental pollution; the specific effect of defined hydrocarbons on the environment, however, is still largely unexplored. Not the least of the reasons for this is that suitable sampling and analysis methods for fluid hydrocarbons are not yet available.
One method that is known is disclosed in "Staub, Reinhaltung der Luft", Vol 47 (1987), No. 1/2, pages 13 ff. In this method, gaseous samples are collected at the surface of adsorption agents present in powder or, respectively, granule form such as Tenax TA, Carbosieve S-II, and Molekularsieb 5A. However, this type of sampling does not make directly available high sample gas concentrations for the analysis step. Concentration of the collected hydrocarbons therefore follows the adsorption of the samples at the surface of the adsorption means. To that end, the hydrocarbons are thermically desorbed and are focused in a cooled capillary. A renewed thermic desorption then follows as does the delivery of the concentrated hydrocarbons to the analysis equipment (a capillary gas chromatograph).